Humidity sensor that is weatherproof/waterresistent

I've been searching for humidity sensors for a long time now, but I was never able to find one that actually appeared to be weatherproof. All those modules that I found had exposed PCBsl and I feel like these are bound to break eventually in the rain/snow etc.

So I'm wondering if anyone of you knows of such a sensor (ideally a module that doesn't require calibration and works out of the box with an Arduino and doesn't cost more than a few bucks). Preferably the module could also measure temperature.

You need something the equivalent of a Stevenson screen to place your sensor in, to keep sun/rain/snow off it.

Sun is not really an issue for me, but rain and snow are. Hm, Stevenson screens seem to be extremely big and expensive. I'd prefer something much smaller. I mean there are plenty of wireless thermometer/hygrometer stations that have all the outdoor sensors in a pretty small box. I thought maybe there is an Arduino sensor in a similar form factor or maybe even something way smaller as I don't need batteries and wireless communication.

Is there maybe a simple way to build something like that myself? I mean it basically just needs to be a box that keeps the water out, but lets the air in, right?

Is condensation going to be an issue?

felic:
I've been searching for humidity sensors for a long time now, but I was never able to find one that actually appeared to be weatherproof. All those modules that I found had exposed PCBsl and I feel like these are bound to break eventually in the rain/snow etc.

So I'm wondering if anyone of you knows of such a sensor (ideally a module that doesn't require calibration and works out of the box with an Arduino and doesn't cost more than a few bucks). Preferably the module could also measure temperature.

Felic, I think I understand your problem, but have you considered that a humidity sensor that is weather proof would not be able to register the humidity.

Have you examined the commercial weather station sensors that monitor the humidity? They are not "weather proof" either. Our outside weather sensor is under the patio roof and has worked flawlessly for 10 years, except for battery replacement. Sure, the air temp is a bit off in the summer, but the humidity sensor is still working ok.

Paul

I use one of these.
s-l225.jpg

It has a sealed case and a ceramic tube which is supposed to allow water vapour but not liquid water through.

I installed it about 6 months ago and so far it works well. It has not been through the winter on a Yorkshire moor yet...

I have it mounted on the north side of a post in a place where it is shaded for the whole day. I mounted it vertically, pointing down, so that rain and snow should drain off it, I hope. I used an ordinary 15mm plumbing pipe clip as the mount.

s-l225.jpg

Have you considered an inverted
glass or plastic jar?

If you have a 3d printer, there lots of ready made deaigns for Stevenson shields to print on thngiverse.

@PaulRB

It has a sealed case and a ceramic tube which is supposed to allow water vapour but not liquid water through.

Thank you for your post. I've been working on an outdoor sensor for some time. I was going to base it on a BME280 sensor. Planning on covering the open end of a small container with some Gore material.

But your suggestion is much better.

Have you had any trouble with RFI interference? From the information on ebay its hard to tell if there is some electrical protection in the device or just a sensor on the end of the wires.

John

I've had no problems with rfi, John. The sensor chip is on a narrow (~5x20mm) PCB inside, with a small cap and pull-up resistors. The cable wires are soldered to pads on the PCB. I know because I had to replace one after an accident with a blown linear regulator blew the chip/PCB also. Purchased a replacement PCB with chip fitted from Ali Express, good as new.

P.S. I'm powering it with 3.3V, don't think its 5V compatible. There's no regulator on the PCB.

@PaulRB That sounds nice. Now that i know what i have to search for, I found several different sensor shells. But now I wonder if there are advantages of using one over the other:

All of those are just the shell. You would have to buy the sensor and cable extra. Then there is a possibility the sensor won't fit inside the shell, or the gland won't seal around the cable. Buying a ready-made set avoids those pitfalls, but gives you less choice about the exact sensor model or cable length.

Those shiny metal ones look nice, but unless they state they are stainless steel, I would avoid, as they will probably rust.

The sensor not fitting could indeed be a problem. I'm not too worries about sealing it. A thick enough cable and some hot glue or silicone should do the trick. But I guess it wouldn't really be worth it to order one just to see it doesn't fit.

May I ask what kind of protocol the sensor you got from ebay is using and which library you used to read the data from the sensor?

My sensors are SHT20, so they use i2c protocol. I will have to look up the library I used later for you, but there are several available.

I've seen this in my travels: Grove AM2315 - Encased I2C Temperature/Humidity Sensor for Raspberry P – SwitchDoc Labs

Adafruit has one too that is more expensive but looks the same: AM2315 - Encased I2C Temperature/Humidity Sensor : ID 1293 : $29.95 : Adafruit Industries, Unique & fun DIY electronics and kits

@alex, you are no longer new to the forum. Please learn how to post links.

From the second link,

it is not rated as 'weatherproof'

The OP did ask

I was never able to find one that actually appeared to be weatherproof...So I'm wondering if anyone of you knows of such a sensor

The library I have used with the sht20 sensors is GitHub - DFRobot/DFRobot_SHT20

@PaulRB Thank you so much! I have ordered my sensors now. :slight_smile:

I got my sensors now. It feels more like plastic and not like ceramic. Anyway, I'll probably try to get it to work with an Arduino later this week.

I bought mine from this seller in case anyone cares.
Only took 10 days to arrive all the way from China.

It looks like the ones I have. The outer casing is plastic, the white tube inside that may be ceramic or plastic, I'm not sure.